I heard the Messenger of Allah ﷺ say: Islam will continue to be triumphant until there have been twelve Caliphs. Then the Prophet ﷺ said something which I could not understand. I asked my father: What did he say? He said: He has said that all of them (twelve Caliphs) will be from the Quraish. (Using translation from Muslim 1821d)
سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ لَا يَزَالُ الْإِسْلَامُ عَزِيزًا إِلَى اثْنَيْ عَشَرَ خَلِيفَةً فَقَالَ كَلِمَةً خَفِيَّةً لَمْ أَفْهَمْهَا قَالَ فَقُلْتُ لِأَبِي مَا قَالَ؟ قَالَ كُلُّهُمْ مِنْ قُرَيْشٍ